The agent was correct, the instant upgrade does not pull from F or A. Instant upgrades on a B fare pull from the PN fare bucket. Therefore for an instant upgrade to be processed at time of booking PN>0. If PN=0, I guess UA is supposed to sweep regularly, but I booked a flight with my TA and had to call UA to manually process the upgrade. When I tried to do it online, UA wanted 10k miles.
Last edited by anc-ord772; Apr 1, 2012 at 10:59 am